Synchronous motors having a primary part having individually wound coils and a secondary part having permanent magnets are described, for example, in U.S. Pat. No. 5,642,013. The primary part has an iron core made of a laminated core stack having multiple teeth of rectangular cross-section. Coils are wound individually around these teeth such that each coil is wound around precisely one tooth.
German Published Patent Application No. 103 18 411 describes a similar linear motor, the primary part of which has multiple coil segments, which are made up of substantially right parallelepiped core stacks, each of which is wound with a coil. These coil segments are connected to one another mechanically and in a magnetically conductive manner on the side facing away from the secondary part so as to produce a primary part similar to the synchronous motor described in U.S. Pat. No. 5,642,013.
Depending on the application, it may be disadvantageous that between the magnets of the secondary part and the core stack of the primary part of such linear motors there are considerable magnetic forces of attraction that must be absorbed by a bearing.
In certain linear motors, these attractive forces are compensated for. European Published Patent Application No. 1 457 826, for example, describes a linear motor having two secondary parts arranged such that the attractive forces of the two magnetic tracks acting on the coil segments cancel each other out. How the individual coil segments may be connected to one another is not described in further detail. The connection of the individual coil segments is problematic especially if a particularly high efficiency factor of the motor is desired, since every screw or every bolt in the core stack deteriorates the efficiency factor or increases the eddy current losses of the motor.